/**
 * Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.
 * An example is the root-to-leaf path 1->2->3 which represents the number 123.
 * Find the total sum of all root-to-leaf numbers.
 * For example,
    1
   / \
  2   3
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.

Return the sum = 12 + 13 = 25.
 */
/**
 * @author Ivan
 *
 */
package problem129_Sum_Root_to_Leaf_Numbers;